Persons who are not totally deaf often hear certain frequencies, usually the low pitch tones, better than other frequencies. Since audible speech is made up of many different frequencies, a person with impaired hearing will typically only hear parts of words, and will therefore have difficulty comprehending what is being said. The problem is further complicated when there is noise in the background, as the frequency of background noise is often in the low end of the hearing range, where the hearing loss is usually the least. Consequently, many persons with impaired hearing rely on lip reading in association with what they are hearing in order to provide an increased level of comprehension, particularly in a noisy listening environment.
One particular situation in which lip reading cannot be used to obtain increased comprehension is where a person with impaired hearing is attempting to carry on a telephone conversation, because the standard telephone transmits only the audible sound.
It is therefore an object of the present invention to provide a device which can increase the ability of a hearing-impaired person to comprehend a telephone conversation, especially in a high background noise situation.